Transcript Structural Designs that Accelerate Corrosion

Steps to a More Effective Power
Tool Cleaning
Presented by: Earl Bowry, Jotun Paints, Inc
Introduction
• This webinar will explain power tool cleaning and how
to effectively remove loose rust, loose mill scale, and
loose paint.
– The presentation will describe two types of power tools,
electrical and pneumatic
– It will describe how the use of high efficiency particulate air
(HEPA) will reduce air pollution
– It will describe how power tools are used for spot cleaning of
damaged coatings, when contamination of adjacent areas by
abrasive is unacceptable and when a surface-tolerant coating
such as oil-based paint is to be used
Power Tool Cleaning
• Is a method of preparing steel surfaces by
the use of power assisted hand held tools
Power Tool Cleaning
• Cleans by impact, abrasion or both
• Used frequently for spot cleaning of
damaged coatings
• Is commonly used to clean difficult to
reach areas or missed areas after
abrasive blasting
• Is used when other forms of surface
preparation are not possible or cost
effective
Power Tool Cleaning
• Two Basic Types:
– Electric
– Air Driven
Power Tool Cleaning
• Pros:
– Can be done in confined areas or where
abrasive blasting will damage sensitive
equipment
• Cons:
– Slow and physically tiring for the operator
– Power tool cleaning media wears out and
has to be replaced during the work
Power Tool Safety
• Eye and face protection is required to
prevent injury caused by flying particles
• Ear protection is required because of the
loud, constant noise
• Wear gloves, boots and hard hats if the
particular job requires it
Power Tool Safety
•
•
•
•
Never run electrical tools in wet areas
Use ground fault interrupters
Use respirators to filter dust and debris
Power tools can create sparks, so take
care when using near volatile vapors and
combustibles
Contractor Safety
Responsibilities
• Provide proper safety equipment for the
job being performed
• Train workers to use the safety
equipment
Worker Safety Responsibilities
• Be familiar with the safety equipment
provided
• Make sure safety equipment is in good
working condition
• You are responsible for your actions!!
Owner Safety Responsibilities
• Assure that proper safety practices are
followed
Types of Power Tools
• 3 different types of power tools used for
surface preparation:
– Impact cleaning tools
– Rotary cleaning tools
– Rotary impact cleaning tools
Common Electrical and Pneumatic
Equipment
• Sanders
• Wire brushes,
wheels & grinders
• Chipping hammers
• Scalers
• Rotary/Impact tools
• Needle guns
Sanders
Important
note:
Grit size and
distribution
(open/closed)
are important
factors
Wire Brushes, Wheels & Grinders
Important
Note:
Wire type and
hardness are
important
factors
Chisel Scaler
Important
Note:
Generally
used for large
scale particle
removal
Flapper Wheels
Use:
Can quickly
remove heavy
layers of rust
and paint.
Rotary/Impact Cleaning
Needle Guns
Important
Note:
Needles
can get dull
fast and
may need
to be
replaced
several
times in a
work shift
Reduction of Air Pollution
• High efficiency particulate air (HEPA)
vacuum lines attached to reduce air
pollution and collect debris produced in
cleaning operation
HEPA
• High-efficiency particulate air
• HEPA is a type of air filter
• To qualify as HEPA by US government
standards, an air filter must remove (from
the air that passes through) 99.97% of
particles that have a size of 0.3
micrometers or larger
Specifications
• The specifications governing power tool
cleaning are:
– SSPC-SP 3, Power Tool Cleaning
– SSPC-SP 11, Power Tool Cleaning to Bare
Metal
– SSPC-SP 15, Commercial Grade Power Tool
Cleaning
– ISO 8504-3, Hand and Power Tool Cleaning
SSPC-SP 1, Solvent Cleaning
• SSPC-SP 3, SSPC-SP 11 and SSPC-SP
15 require removal of all oil, grease, dirt,
etc. in accordance with SSPC-SP 1,
Solvent Cleaning, before cleaning with
power tools
SSPC-SP 3, Power Tool Cleaning
• Removal of loose rust, loose mill scale,
and loose paint to degree specified
• Intact materials may remain such as:
– Mill scale
– Rust
– Paint
• Materials considered intact if they cannot
be removed by lifting with a dull putty
knife
SSPC-SP 3, Power Tool
Cleaning
• Specified when rigorous surface
preparation is not required, such as a dry
interior
SSPC-SP 11, Power Tool
Cleaning to Bare Metal
• Remove tightly adherent materials to produce a
surface that is visibly free from all rust, mill scale
and old coatings
• No staining permitted
• Slight residue permitted in bottom of pits if the
original surface was pitted
• Requires a 1 mil minimum surface profile
SSPC-SP 11, Power Tool
Cleaning to Bare Metal
• Examples of circumstances where this
specification may be applied are:
– Touch-up of welded or damaged areas of
erection assemblies
– Reducing volume of hazardous waste
produced by abrasive blasting
– Cleaning around sensitive equipment or
machinery
SSPC-SP 15, Commercial
Grade Power Tool Cleaning
• Requires the removal of all paint, rust, mill
scale and other foreign matter
• Allows random staining on 33% of each
unit area (9 in2)
• Slight residue permitted in bottom of pits if
the original surface was pitted
• Requires a 1 mil minimum surface profile
ISO 8501
• Combines hand and power tool cleaning
in one standard
• Has two grades of Cleaning:
– St 2 – Remove all oil, dirt and poorly
adhering mill scale, rust, paint and foreign
matter
– St 3 – Same as St 2 but more thoroughly
cleaned until a metallic sheen is observed
Surface Profile
• ASTM D4417, Method B (Unless
Otherwise Specified)
– Digital Surface Profile depth micrometer
Profilometer
Surface Profile: SSPC-PA 17
• Procedure for Determining Conformance to
Steel Profile/Surface Roughness/Peak
Count Requirements
– Describes a procedure suitable for shop or field
use for determining compliance with specified
profile ranges on a steel substrate
SSPC-VIS 3
• Guide and
Reference
Photographs for
Steel Surfaces
Prepared by Powerand Hand-Tool
Cleaning
SSPC-VIS 3
• This guide describes the use of reference
photographs depicting the appearance of
unpainted, painted, rusted, and welded
hot-rolled carbon steel prior to and after
power and hand tool cleaning
• These photographs are intended to be
used to supplement the written SSPC
power and hand tool surface preparation
standards
SSPC-VIS 3 Initial Conditions
• Condition A: Steel surface completely
covered with adherent mill scale; little or no
rust visible
• Condition B: Steel surface covered with
mill scale and rust
• Condition C: Steel surface completely
covered with rust; little or no pitting visible
SSPC-VIS 3 Initial Conditions
• Condition D: Steel surface completely
covered with rust; pitting visible
• Condition E: Previously painted steel
surface; light colored paint applied over
blast cleaned surface, paint mostly intact
• Condition F: Previously painted steel
surface; zinc-rich paint applied over blast
cleaned steel, paint mostly intact
SSPC-VIS 3 Initial Conditions
• Condition G:
Painting system
applied over mill
scale bearing
steel; system
thoroughly
weathered,
thoroughly
blistered, or
thoroughly stained
SSPC-VIS 3 Steps
• Determine initial condition of steel
– Select the photograph of the condition that most
closely represents the appearance of the steel to be
cleaned
• Determine the power tool cleaning level to be achieved
(SP 3, 11 or 15)
• Select the tool to achieve the specified level of
cleanliness
• Use the photos in VIS 3 that represent the end condition
based on the proper tool and specified level of
cleanliness (i.e., SP 3/PWB)
Summary
• Use of portable power tools- pneumatic
and electric- is common for cleaning
operations. Through careful selection
and use of the great variety of power
tools and accessories, many cleaning
operations can be accomplished rapidly
and produce satisfactory surface
conditions with reasonable labor costs
and good paint life
• Questions?????